"Thermo" simply means heat; all "vacuum-forming" processes require heating thermo-plastic material to form them. Thermo-set plastics (of which epoxy is one) do not "melt" when heated, they may distort to a certain degree, but they never become "formable".

But there are a lot of variations on the process, especially in the area of "packaging", versus, "product" molding; material gauge (thickness), cycle times, and auto-trim capabilities being the notable differences.

As LMO pointed out, there is no difference between the terms you used.

But there are several types of thermoforming.

Straight thermoforming is using heat to soften the material (plastic and foams) and then using a male and female molds to compress the material into shape. Undercuts are possible but only as a secondary process. This is very popular for molding PE foam laminated to a woven cloth.

Vacuum assist thermoforming is what has been discussed. It can be either male or female molds. That choice is usually determined on which will provide the least amount of webbing. The heating element can be simple, it heats the entire sheet of material, or it can heat only specific area of the sheet. This is done to keep wall thickness consistant.

You can also have a plug assist, vacuum assist thermoforming. Not quite a male/female mold, the plug generally pushes the material down into the mold and does not exactly match the mold form. Again, this is used to keep wall thickness consistant. Which is very important for strength and barrier qualities and when you want a deeper draw into the mold.

Finally you can have a form/fill/seal. These will have the bottom web as a plug assist, vacuum assist thermoform while the top web is typically a film that is heat-sealed to the bottom web after whatever parts have been put into the formed bottom web. Think frozen dinners. The top web can also be formed, but I don't think it is as common.

As a rule of thumb (or wrist for you Boondock Saints fans), your maximum Z draw is equal to the smaller of the X or Y dimension. Of course there are exceptions based on design and materials choice.

Since vacuum assisted thermoforming is so commonly used, you would think there would be software to simulate this process so the designer can estimate part geometry and strength before going into production. I haven't seen this type of application, does anyone know of it?

ralphzoontjens wrote:Since vacuum assisted thermoforming is so commonly used, you would think there would be software to simulate this process so the designer can estimate part geometry and strength before going into production. I haven't seen this type of application, does anyone know of it?